im not to up on these motors yet
what are the difference between the 94-98 to 99-04 4.6s
i wanna pick up a long block to build for boost

also if i grab a 4.6 from like a town car or somthing does it really make a difference

 

PI Heads?

 

ya i have a o1 now i just wanna get a backup motor and start building it

 

PI heads, there are two engines, Cleveland and Windsor, both are essentially identical with the exception of some accessory mount bolt sizes and flywheel bolts, at least on the 4.6 SOHC.
Those two come to mind Hursty probably knows a bunch more since he's the resident Ford guru.